Exhaust back pressure reducer for internal combustion engines



B. PAGLIUCA 3,045,421

EXHAUST BACK PRESSURE REDUCER FOR INTERNAL COMBUSTION ENGINES July 24, 1962 Filed Deg. 19, 1960 INVEN TOR. Ba '/'0 Pag/iuca Alfomey Fig.4

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3,045,421 EXHAUST BACK PRESSURE REDUCER FOR INTERNAL COMBUSTION ENGWE Basilio Pagliuca, 3198 W. 7th St, Los Angeles, Calif. Filed Dec. 19, 1960, Ser. No. 75,857 3 Claims. (Cl. 60-30) This invention relates to a novel and improved exhaust back pressure reducer for internal combustion engines and more particularly to an improved back pressure reducer which creates an effective suction on the tail pipe of the engine exhaust system thereby reducing the back pressure within the mufiler and eflectively the entire exhaust system.

Heretofore, some devices of this type have attempted to accomplish this result by scooping air into the tail pipe or exhaust conduit and mixing this air with the exhaust gases inside the tail pipe. Such devices are dependent for their efiectiveness solely upon the velocity of air injected directly into the exhaust conduit. Such devices efiectively succeed only in ottsetting any accomplished pressure reduction by increasing the pressure in the exhaust system an amount equal to or greater than the original reduction which was hoped for. Other such devices have attempted to accomplish a pressure reduction in the exhaust system by providing an air scoop externally of the tail pipe. These devices accomplish, it anything, nothing more thana mere diffusion of the exhaust gases with air after emission from the tail pipe or end of the exhaust conduit.

One object of this invention, is to provide an exhaust back pressure reducer for an internal combustion engine which creates a negative pressure at the terminus or end of the tail pipe or exhaust conduit thereby effectively lowering the pressure within the muffier and effectively the entire exhaust system.

Another object of this invention is to provide an exhaust pressure reducer for an internal combustion engine which eifectively so reduces the back pressure within the muffler and entire exhaust system as to increase the efficiency of the engine itself with an accompanying increase of power and speed of the engine While at the same time increasing the gasoline mileage of the vehicle driven by the engine.

Briefly described, my invention utilizes the bournelli or venturi effect to create an effective suction within the exhaust conduit and particularly the muflier at approximately the terminus or end of the exhaust conduit. This is accomplished by providing a venturi reducer with the end of the tail pipe or exhaust conduit located in the throat of the venturi at the point Where the velocity is greatest and the pressure is the lowest.

Other objects and advantages of this invention will become apparent as the discussion proceeds and when taken in connection with the accompanying claims and drawings in which:

FIGURE 1 shows a perspective view partially broken away of the principal embodiment of my invention;

FIGURE 2 shows an end plan view of the principal embodiment of my invention shown in FIGURE 1;

FIGURE 3 shows a cross sectional view of the principal embodiment of my invention taken along the line 3-3 of FIGURE 2; and

FIGURE 4 shows an end plan view of a modified embodiment of my invention. 7

Turning now to a detailed description of my invention, the numeral 6 designates a mufiier of a conventional exhaust system of an internal combustion engine. The unmeral 10 designates a conventional exhaust conduit or tail pipe leading from the mufiler 6.

The preferred embodiment of my invention contem- $345,421 Patented July 24, 1952 ice plates a structure which is adapted as a su or tail pipe extension. While I have illustrated my invention in this manner, it is to be understood that the spirit of this invention can be accomplished by constructing a device embodying my invention as an integral part of the tail pipe 15. Numeral 14 designates a tubular member having an inside diameter just sufficiently large enough to snugly slide over the outside of the end of the tail pipe 10. A screw 16 is provided on the tubular member 14 for the purpose of clamping the same onto the tail pipe 10. If desired, the screw 16 could be omitted and the tubular member 14 clamped to the tail pipe by means of a clamp or by welding. The numeral 18 designates generally a back pressure reducer or venturi pressure reducer embodying my invention, which hereinafter, for the sage of simplicity shall be referred to as a 'venturi pressure reducer or reducer. I

The reducer 18 comprises a top member or plate 19 and a bottom member or plate 20 which are closed together by end plates 22; and 24. Afiixed to the inside of plate 22 and also to plate 2.4, to form a modified venturi is a restrictive member 26 and 28. The restrictive members 26 and 28 are shaped in the form of a conventional venturi as best shown in FIGS. 1 and 3, and when associated with the top plate 19 and bottom plate 20 complete the modified venturi structure. The throat of the venturi, as in a conventional venturi, and designated as that section lying between lines 3032, is that area in the venturi of the lowest pressure, created by the movement of air therethrough at its maximum velocity.

or the restrictive members as '34 and 36 respectively and the downstream faces 38 and 40 respectively. The end of tail pipe 14 is designated by the numeral 42. Bolts or screws 44 and 46 pass through the top plate 19 and bottom plate 20 to secure the reducer 18 onto the sub or tail pipe extension 14. The end 42 of the tail pipe extension is positioned within the throat of the venturi and in the area lying between lines 30 and 32.

While the precise location of the end 42 of the tail pipe extension within the throat area (ML-32) within the venturi is important, it is critical only within that range dictated by dynamic principles. This position will vary in accordance with the air velocities to be encountered. For example, in the drawings, I have illustrated this position as being at the narrowest point in the throat. This has been found to be more desirable for ordinary speeds and conditions encountered in operating the average vehicle. If higher or lower speeds are to be encountered, the end 42 of the tailpipe extension will be moved upstream or downstream. In order to accommodate this variation, 2. slot 43 is provided in the tail pipe extension 14, as shown in FIGS. 1 and 3. The restrictive members 26 and 28 are attached to the end plates 22 and 24in any suitable manner as by welding, crimping or the like.

In the modification shown in FIG. 4, the construction of my invention is substantially the same as that shown in FIGS. 1, 2 and 3 with the exception that the tail pipe or sub 14 is modified from round to square or rectangular and is designated generally by the numeral 50. Also, the square or rectangular sub 50' is spaced apart from the. top and bottom walls of'the rectangular member 18 by means of a spacer 52 at the top and a second spacer 54 at the bottom. The sub 50 is a lixed to the member 18 by means of bolts 56 and 58, the same as is sub 14 in FIGS. 1, 2 and 3. The advantage of this modification is that it gives a more rugged construction and permits, under certain conditions, a greater flow of air around the sub 50, and permits the making of the air scoop or venturi 1% smaller with an equal effectiveness.

Further in explanation of the operation of my invention, air designated generally by lines referred to as as, is scooped in by the forward movement of the vehicle and is compressed to its maximum and forced into its greatest velocity in the throat of the venturi between the lines and 32. This area is that of lowest pressure and creates a vacuum in the zone immediately outside the end 42 of the stub 14. Thus partial vacuum or suction will then withdraw gases from within the exhaust system and particularly within the muffler 6, thereby eifectively reducing the back pressure within the entire exhaust sys tem completely back into the exhaust manifold of the internal combustion engine connected to the exhaust system. There'will also be a temperature diiferential between the hot gases emitting from the exhaust and the air scooped in by the venturi. Additional pressure drop across the end 42 from this will also be obtained.

It has been found that there is a sufiicient vacuum or suction on the end of the exhaust system created by the particular arrangement of my invention, so as to give an appreciable increase in horsepower to the operation of the internal combustion engine, and at the same time give an appreciable increase in gas mileage.

It is to be understood from the foregoing, that the precise ratio of the cross sectional area of the opening formed by the top and bottom plates 19 and 2t), and the venturi throat lying between lines 30 and 32, as compared to the cross sectional area of the opening of the member 14, can vary within limits dictated by well known dynamic principles. In the preferred embodiment of my invention, the cross sectional area of opening between the venturi at its throat and the exhaust conduit should be substantially equal to the cross sectional area of the exhaust. It is also to be understood that varying conditions as for example,.the cross sectional area of the air scoop opening designated at end 70 in FIG. 3, as Well as the particular shape of the venturi can be resorted to to give modifying effects for various conditions of usage without departing from the spirit of my invention.

It is also to be understood that various changes in composition of material and changes in outside configuration shape of the venturi or scoop 18 can be resorted to without departing from the spirit of this invention, as set forth in the appended claims.

What is claimed is:

1. An exhaust pressure reducer for an internal combustion engine comprising a tubular member adapted to fit over the end of the exhaust conduit of said internal combustion engine, a venturi mounted on said tubular member, said venturi having an elongated flat top and bottom plate, a pair of inwardly flaring arcuate side members located intermediate said top and bottom plates and being in spaced apart relation to form a venturi throat approximately equal in cross-sectional area to the crosssectional area of the end of said tubular member, adjustable slotted means associated with said top member, said bottom member and said tubular member whereby the position of the end of said tubular member can be longitudinally and accurately adjusted in respect to the throat of said venturi, said adjustable slotted means comprising a first elongated adjustable slotted means associated with said top plate and said tubular member and a second elongated adjustable slotted means associated with said bottom plate and said tubular member and positive clamping means associated with each of said slotted means for positively clamping said tubular member to said top and bottom plates after the desired adjustment is made.

2. An exhaust pressure reducer for an internal combustion engine comprising a tubular member adapted to fit over the end of the exhaust conduit of said internal combustion engine, a venturi mounted on said tubular member, said venturi having an elongated fiat top and bottom plate, a pair of inwardly flaring arcuate side members located intermediate said top and bottom plates and being in spaced apart relation to form a venturi throat approximately equal in cross sectional area to the crosssectional area of the end of said tubular member, said tubular member having a pair of elongated slots disposed apart extending longitudinally of said tubular memher and located adjacent the end thereof, and a first clamping means on the top plate and a second clamping means on the bottom plate inserted through each of said slots to permit a longitudinal and accurate adjustment of the end of said tubular member in respect to the throat of said venturi and also to permit positive and accurate clamping of the venturi onto the tubular member after the end of said tubular member is adjusted in respect to the throat of said venturi.

3. An exhaust pressure reducer for an internal combustion engine comprising a tubular member adapted to fit over the end of the exhaust conduit of said internal combustion engine, a venturi mounted on said tubular member, said venturi having an elongated flat top and bottom plate, a pair of inwardly flaring arcuate side members located intermediate said top and bottom plates and being in spaced apart relation to form a venturi throat approximately equal in cross-sectional area to the crosssectional area of the end of said tubular member, said top plate having an elongated slot extending in a direction parallel to the sides of said venturi, said bottom plate having an elongated slot extending parallel to the sides of said venturi and clamping means on said tubular member associated with each of said slots to permit a longitudinal and accurate adjustment of the end of said tubular member in respect to the throat of said venturi and also to permit positive and accurate clamping of the venturi onto the tubular member after the end of said tubular member is adjusted in respect to the throat of said venturi.

References Cited in the tile of this patent FOREIGN PATENTS 980,515 France Dec. 27, 1950 804,440 Great Britain Nov. 12, 1958 411,522 Italy Aug. 10, 1945 

